Apparatus for feeding raw material into a quartz crucible

ABSTRACT

A method of an apparatus for automatically and rapidly feeding raw material into a quartz crucible in manufacture of single-crystal silicon by CZ method. After a draining hose 203 is disposed in a quartz crucible 201, pure water is supplied from a water supply hose 204, and the quartz crucible 201 is conveyed onto a turn table 213 installed under a container 210. At this time, the quartz crucible 201 is rotated, and lump raw material 209 is fed into the quartz crucible 201. Since buoyancy of the pure water is applied to the lump material 209, impacts caused by the falling lump material can be moderated, and therefore, damages to the quartz crucible 201 can be prevented. After feeding raw material is finished, the pure water is discharged through a draining hose 203, and then the draining hose 203 is retracted from the quartz crucible 201. Thereafter, the quartz crucible 201 is conveyed into a microwave oven 211 for drying.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to apparatus and a method and for feeding rawmaterial into a quartz crucible during manufacture of single-crystal byCZ method.

2. Description of the Prior Art

High-purity single-crystal silicon is mainly used as substrates insemiconductor manufacturing. Generally, a method for manufacturingsingle-crystal silicon is based on the CZ method. In the CZ method, aquartz crucible into which lump polycrystalline silicon materials arefed, is disposed inside an apparatus for manufacturing single-crystalsilicon. The lump polycrystalline silicon is melted into a melt by aheater surrounding a quartz crucible. Furthermore, after dipping a seedwhich is disposed on a seed holder into the melt, the seed holder andquartz crucible rotate in the same direction or in opposite directions.Meanwhile the seed holder is pulled to grow single-crystal silicon.

In the CZ method, a predetermined amount of polycrystalline siliconmaterial must be fed into the quartz crucible before manufacturing thesingle-crystal silicon. The polycrystalline silicon is lumpy, has acuteangles and extremely high hardness. Moreover, since the quartz crucibleis brittlepiece, a lump of polycrystalline silicon with 20˜110 mm insize, which occupies over 90% volume of the quartz crucible, is fed intothe quartz crucible by man-hand in order to prevent the crucible beingbroken. Therefore, feeding raw material is a really simple operation,but the using time for feeding raw material, in particular formanufacturing larger single-crystal silicon, become more longer.

SUMMARY OF THE INVENTION

In light of the above drawbacks, the object of the present invention isto provide a method and an apparatus capable of rapidly feedingpolycrystalline silicon lumps (raw material) into a quartz cruciblewithout any hand operation in the process of manufacturing siliconsingle-crystal employing the CZ method.

A first aspect of the apparatus for feeding raw material into acrucible, used for feeding polycrystalline silicon as raw material intoa crucible before manufacturing silicon single crystal by the CZ method,is an apparatus of the present invention, which comprises:

means for feeding polycrystalline silicon lumps into the crucible;

means for covering the inner wall of the crucible with a buffer of anyone or a mixture of those selected from the group of pieces ofpolycrystalline silicon, grains of polycrystalline silicon, pure-watersnow, sherbet-shaped pure-water ice, pure-water ice pieces, andpure-water ice;

means for draining the liquid melted from the buffer from the crucible;and

means for drying the crucible and the polycrystalline silicon fed intothe crucible.

A second aspect of the apparatus is an apparatus according to the firstaspect, further comprising the means for rotating and transporting thecrucible.

A third aspect of the apparatus is an apparatus according to the firstaspect, further comprising:

a resin tube capable of covering the inner sidewall of the crucible;

means for moving up and down the above resin tube within a predeterminedrange; and

means for rotating the rosin tube at a speed equivalent to that of thecrucible.

A fourth aspect of the apparatus in an apparatus according to the firstaspect, further comprising:

means for moving up and down said feeding means and said covering meanswithin a predetermined range and moving them in the horizontal directionreciprocally.

A fifth aspect of the apparatus is an apparatus according to the firstaspect, further comprising:

means for automatically controlling at least one of said means forfeeding polycrystalline silicon lumps; means for covering;

means for draining; and

means for drying.

A sixth aspect of the apparatus is an apparatus according to the firstaspect, wherein

the draining means comprise a draining hose, a insert part of which isinserted into the crucible so as to drain the liquid melted from thebuffer and the insert part is made of one of a polycrystalline siliconpipe, a single-crystal silicon pipe with a purity essentially the sameas that or polycrystalline silicon lumps;

and a pipe coated by a polycrystalline silicon pipe or a single-crystalsilicon pipe with a purity essentially the same as that of thepolycrystalline silicon lumps.

A seventh aspect of the method of feeding raw material into a cruciblebefore pulling silicon single crystal from the crucible by the CZ methodis a method of the present invention, which comprises the steps of:

covering the inner wall surface of the crucible with a buffer of any oneor a mixture of those selected from the group of pieces ofpolycrystalline silicon, grains of polycrystalline silicon, pure-watersnow, sherbet-shaped pure-water ice, pure-water ice pieces, orpure-water ice before feeding polycrystalline silicon lumps an rawmaterial into the crucible;

feeding polycrystalline silicon lumps as raw material into the crucible;

pouring pure water into the crucible to melt the buffer left therein soas to expel the water out of the crucible after the stop of feeding

drying the crucible and the polycrystalline silicon lumps in thecrucible.

A eighth aspect of the method is a method according to the seventhaspect, wherein the pouring step comprises a step of pouring a heatedwater into the crucible.

A ninth aspect of the method is a method according to the seventhaspect, wherein

the steps of covering further comprises the steps of covering thecovered inner wall surface of the crucible with any one or a mixture ofpure-water snow or pure-water ice pieces.

A tenth aspect of the method is a method according to the seventhaspect, wherein the steps of covering comprises a step of fixing a ringshaped pure-water ice to the inner sidewall surface of the crucible.

An eleventh aspect of the method is a method according to the tenthaspect, wherein

the steps of covering further comprises the steps of covering thecovered inner wall surface of the crucible with a second buffer of anyone or a mixture of those selected from pieces of polycrystallinesilicon, grains of polycrystalline silicon, pure-water snow, orpure-water ice pieces.

A twelfth aspect of the method is a method according to the seventhaspect, wherein

the steps of covering comprises the steps of:

covering at least the bottom part of the inner surface of the cruciblewith the buffer; and

covering the inner sidewall of the crucible with a resin tube capable ofmoving up and down.

A thirteenth aspect of the method in a method according to the twelfthaspect, wherein

after feeding polycrystalline silicon lumps, the resin tube is moved upand withdrawn from the crucible.

A fourteenth aspect of the method is a method according to thethirteenth aspect, wherein

the resin tube is gradually raised in response to the progress offeeding the polycrystalline silicon lumps, and the resin tube iscompletely withdrawn from the crucible at the end of feeding thepolycrystalline silicon lumps.

A fifteenth aspect of the method of feeding raw material into a cruciblebefore pulling silicon single crystal from the crucible by the CZ methodis a method of the present invention, comprising the steps of:

covering the inner wall surface of the crucible with a buffer ofpiece-shaped or grain-shaped polycrystalline silicon before feedingpolycrystalline silicon lumps as raw material into the crucible;

covering the inner sidewall of the crucible with a resin tube capable ofmoving up and down; and

feeding polycrystalline silicon lumps as raw material into the crucible.

A sixteenth aspect of the apparatus is an apparatus according to thefirst aspect, further comprising:

means for supplying pure water into a crucible.

A seventeenth aspect of the apparatus is an apparatus according to thesixteenth aspect, further comprising:

a bucket for containing said crucible which is deeper than saidcrucible; and

means for moving said crucible out of said bucket.

An eighteenth aspect of the apparatus in an apparatus according to thesixteenth aspect, further comprising:

a tube for covering the inner sidewall of said crucible; and

means for moving said tube upward and downward within a predeterminedrange.

A nineteenth aspect of the method of feeding raw material into acrucible before pulling silicon single crystal from the crucible by theCZ method is a method of the present invention, comprising the steps of:

filling a crucible with pure water; and

feeding lump polycrystalline silicon as raw material into said purewater.

A twentieth aspect of the method of feeding raw material into a cruciblebefore pulling silicon single crystal from the crucible by the CZ methodis a method of the present invention, comprising the steps of:

disposing a crucible into a bucket deeper than said crucible;

filling said crucible and said bucket with pure water; and

feeding lump polycrystalline silicon into said crucible.

A twenty first aspect of the method is a method according to thenineteenth aspect, further comprising:

feeding small piece-shaped or grain-shaped of polycrystalline silicon ortheir mixture with a predetermined thickness on the bottom of saidcrucible before feeding said lump polycrystalline silicon.

A twenty second aspect of the method is a method according to thenineteenth aspect, further comprising:

feeding piece-shaped or sherbet-shaped ices or their mixture made ofpure water into said crucible before feeding said lump polycrystallinesilicon.

A twenty third aspect of the method is a method according to thenineteenth aspect, further comprising:

feeding piece-shaped or grain-shaped polycrystalline silicon or theirmixture, and piece-shaped or sherbet-shaped ices or their mixture madeof pure water into said crucible before feeding said lumppolycrystalline silicon.

A twenty fourth aspect of the method is a method according to thenineteenth aspect, further comprising:

covering the inner sidewall of said crucible with a tube which can befreely moved upward and downward; and

moving said tube out of said crucible upon the and of feeding said lumppolycrystalline silicon, or raising the tube corresponding to theprocess of feeding said lump polycrystalline silicon and moving saidtube out of said crucible completely upon ending the feeding of saidlump polycrystalline silicon.

A twenty fifth aspect of the method is a method according to thenineteenth aspect, further comprising:

drying said polycrystalline silicon and said crucible after feeding lumppolycrystalline silicon as raw material. ilicon as raw material.

To achieve the above object, a first apparatus according to thisinvention, for feeding raw material into a quartz crucible is used forfeeding polycrystalline silicon into a quartz crucible beforemanufacturing silicon single crystal by the CZ method, which ischaracterized in that: it comprises means for feeding polycrystallinesilicon lumps into the quartz crucible; means for covering the innerwall surface of the quartz crucible with any one or a mixture of thoseselected from the group of pieces of polycrystalline silicon, grains ofpolycrystalline silicon, pure-water snow, pure-water ice pieces, orpure-water ice; means for draining the liquid melted from any one or amixture of those selected from the group of the above pure-water snow,the above pure-water ice pieces, or the above pure-water ice from thequartz crucible; means for drying the quartz crucible and thepolycrystalline silicon fed into the quartz crucible; and means forrotating and transporting the quartz crucible.

Raw material of silicon single crystal, namely, polycrystalline siliconcan be automatically deposited into the quartz crucible without handoperation. Since pieces of polycrystalline silicon, grains ofpolycrystalline silicon, pure-water snow, pure-water ice pieces, orpure-water ice is disposed between the inner wall surface of the quartzcrucible and polycrystalline silicon lumps as shock-absorption material,the shock imposing on the quartz crucible during the feeding of thepolycrystalline silicon lumps could be absorbed. In addition to themeans for feeding polycrystalline silicon lumps, the raw materialfeeding apparatus according to this invention is provided with the abovemeans for feeding shock-absorption material, therefore the breakage ofthe quartz crucible can be avoided. In addition, after raw material hasbeen fed into the quartz crucible, pure-water snow, or pure-water icepieces is brought to melt into water and expelled out of the quartzcrucible. Afterwards, the quartz crucible is conveyed into raw materialdrying device to dry them together with raw material.

Furthermore, a second apparatus according to this invention, for feedingraw material into a quartz crucible is characterized in that: further tothe above first apparatus for feeding raw material into the quartzcrucible, a resin tube capable of loosely covering the inner sidewall ofthe quartz crucible; means for moving up and down the above resin tubewithin a preset magnitude; and means for rotating the above resin tubeat a speed equivalent to that of the quartz crucible are respectivelyprovided.

In the above apparatus for feeding raw material into a quartz crucible,a shock-absorption means for absorbing the shock imposing on the innersidewall surface of the quartz crucible during the feeding of thepolycrystalline silicon lumps is the above resin tube. The above resintube descends so as to cover the inner sidewall surface of the quartzcrucible during feeding the polycrystalline silicon lumps. Also, theabove resin tube is rotated at a speed equivalent to that of the quartzcrucible, therefore no friction is incurred between the inner sidewallsurface of the quartz crucible and the polycrystalline silicon lumps fedthereinto.

Furthermore, further to the above first and second apparatuses forfeeding raw material into the quartz crucible, means for moving up anddown the feeding means and the covering means within a preset magnitudeand moving them in the horizontal direction reciprocally is furtherprovided. The feeding means is used for feeding polycrystalline siliconlumps into the quartz crucible. The covering means is used for coveringthe inner wall surface of the quartz crucible with any one or a mixtureof those selected from the group of pieces of polycrystalline silicon,grains of polycrystalline silicon, pure-water snow, pure-water icepieces, or pure-water ice.

Moving up and down the means for covering the inner wall surface of thequartz crucible with piece/grain raw material, snow, ice pieces, orpure-water ice, moving the covering means in the horizontal directionreciprocally, and rotating the quartz crucible keeps the aboveshock-absorption material covering the inner wall surface of the quartzcrucible with an even thickness. This can protect the quartz cruciblefrom the impact induced by dropping of the polycrystalline silicon lumpsin a subsequent process. Also, moving up and down the means for feedingpolycrystalline silicon lumps into the quartz crucible, moving it in thehorizontal direction reciprocally, and rotating the quartz crucibleenables the polycrystalline silicon lumps to be fed in a dense mannerthe same as that done by hands conventionally.

In order to automatically drive each of the above mentioned means, theapparatus for feeding raw material into a quartz crucible in accordancewith this invention is characterized in that: means for automaticallycontrolling each of the above mentioned means is provided.

In the first and second apparatuses for feeding raw material into aquartz crucible in accordance with this invention, the entire process offeeding polycrystalline silicon lumps, covering the quartz crucible withshock-absorption material prior to feeding the polycrystalline siliconlumps, and treating the polycrystalline silicon subsequent to feedingthe polycrystalline silicon can be automatically controlled.

Furthermore, this invention is characterized in that: in the apparatusfor feeding raw material into a quartz crucible, the insert port forinserting an draining hose into the quartz crucible so as to expel theliquid melted from any one or a mixture of those selected from the groupof pure-water snow, pure-water ice pieces, or pure-water ice out of thequartz crucible is a polycrystalline silicon pipe or a single-crystalsilicon pipe with a purity essentially the same as that ofpolycrystalline silicon lumps. Alternatively, the above insert port issheathed by a polycrystalline silicon pipe or a single-crystal siliconpipe with a purity essentially the same as that of polycrystallinesilicon lumps.

According to the above structure, at least the insert port of thedraining hose used for draining water out of the quartz crucible in apolycrystalline silicon pipe or a single-crystal silicon pipe with apurity essentially as same as that of the raw material fed into thequartz crucible, or the insert port is sheathed by a polycrystallinesilicon pipe or a single-crystal silicon pipe. Therefore, when thedraining hose is pulled out from the quartz crucible subsequent to thedraining of water, the friction between the pipe and the raw materialfed into the quartz crucible will not produce impurities.

A method of feeding raw material into a quartz crucible by usingpure-water snow or pure-water ice as a shock-absorption material ischaracterized in that: before manufacturing silicon single crystal bythe CZ method, in the process of feeding polycrystalline silicon lumpsinto the quartz crucible, the inner wail surface of the quartz crucibleis covered with any one or a mixture of those selected from the group ofpieces of polycrystalline silicon, grains of polycrystalline silicon,pure-water snow, pure-water ice pieces, or pure-water ice; thenpolycrystalline silicon lumps is deposited into the quartz crucible;subsequently pure water or hot pure water is poured into thepolycrystalline silicon lumps to melt the snow, ice pieces left thereinso as to expel water out of the quartz crucible after thepolycrystalline silicon lumps has been deposited a preset amount;thereafter the quartz crucible and the polycrystalline silicon lumps fedinto the quartz crucible are brought to dry.

By employing the above method, the shock during the feeding of thepolycrystalline silicon lumps could be absorbed by the snow, ice pieceswhich is covering the inner wall surface of the quartz crucible; orabsorbed by the mixture of pieces of polycrystalline silicon, grains ofpolycrystalline silicon, snow, or ice pieces which is tightly packed onthe bottom of the quartz crucible. Therefore, the breakage of the quartzcrucible can be prevented. Furthermore, pure water or hot pure water ispoured into the polycrystalline silicon lumps to melt the remained snow,ice pieces after the polycrystalline silicon lumps has been fed a presetamount, therefore impurities sticking on raw material can be washed offand expelled out of the quartz crucible. Furthermore, after draining thewater containing the above impurities, if the quartz crucible and thepolycrystalline silicon lumps fed into the quartz crucible are broughtto dry, then the single-crystal manufacturing device employing the CZmethod is ready to be operated.

In the first method for feeding raw material into a quartz crucible byusing snow and ice as a shock-absorption material is characterized inthat: in the process of feeding raw material into the quartz crucible,the inner wall surface of the quartz crucible is covered with any one ora mixture of pure-water snow, or pure-water ice pieces, or the bottom ofthe quartz crucible is tightly packed with any one or a mixture ofpieces of polycrystalline silicon or grains of polycrystalline silicon;then the inner wall surface of the quartz crucible is covered with anyone or a mixture of pure-water snow or pure-water ice pieces.

According to the above method, then the inner wall surface of the quartzcrucible is covered by pure-water snow, pure-water ice pieces, pieces ofpolycrystalline silicon, or grains of polycrystalline silicon, thereforethe shock during the feeding of the polycrystalline silicon lumps couldbe completely absorbed.

In the second method for feeding raw material into a quartz crucible byusing snow and ice an a shock-absorption material is characterized inthat: the inner sidewall surface of the quartz crucible is covered by alink shaped pure-water ice which is inserting thereinto.

According to the second method for feeding raw material into a quartzcrucible, the protection to the inner sidewall surface of the quartzcrucible is enhanced, therefore the impact imposing on the innersidewall surface of the quartz crucible could be impeded when thepolycrystalline silicon lumps is fed into the quartz crucible.

In the third method for feeding raw material into a quartz crucible byusing snow and ice as a shock-absorption material is characterized inthat: the entire inner wall surface of the quartz crucible is covered bypure-water ice, or alternatively the entire inner wall surface of thequartz crucible is covered by pure-water ice and additionally any one ora mixture of those selected from pieces of polycrystalline silicon,grains of polycrystalline silicon, pure-water snow, or pure-water icepieces is tightly packed over the above pure-water ice; thenpolycrystalline silicon lumps is fed into the quartz crucible

According to the third method, an integrally formed pure-water icecovers the entire inner wall surface of the quartz crucible, thereforethe ice reaching melting temperature and the water layer producedbetween the ice and the quartz crucible can be used as ashock-absorption material Pure-water snow, pure-water ice pieces, piecesof polycrystalline silicon, or grains of polycrystalline silicon can betightly packed on the integrally formed pure-water ice. Therefore, theimpact imposing on the quartz crucible could be absorbed by the ice andthe water layer, the snow, or the ice pieces when the polycrystallinesilicon lumps is fed into the quartz crucible. Accordingly, the quartzcrucible could be protected from the impact.

In the fourth method for feeding raw material into a quartz crucible byusing snow and ice as a shock-absorption material is characterized inthat: the bottom of the quartz crucible is covered with any one or amixture of pieces of polycrystalline silicon, grains of polycrystallinesilicon, pure-water snow, or pure-water ice pieces; then the innersidewall of the quartz crucible is covered with a resin tube capable ofmoving up and down without restraint.

According to the fourth method, pieces of polycrystalline silicon,grains of polycrystalline silicon, pure-water snow, or pure-water icepieces protect the bottom of the quartz crucible, and the resin tubeprotects the inner sidewall of the quartz crucible. Therefore, theimpact imposing on the quartz crucible could be completely impeded whenthe polycrystalline silicon lumps is fed into the quartz crucible.

The fifth method for feeding raw material into a quartz crucible ischaracterized in that: in the fourth method, the bottom of the quartzcrucible is covered with any one or a mixture of pieces ofpolycrystalline silicon, grains of polycrystalline silicon, pure-watersnow, or pure-water ice pieces; then the inner sidewall of the quartzcrucible is covered with a resin tube capable of moving up and downwithout restraint; at the end of feeding polycrystalline silicon lumps,the resin tube is withdrawn from the quartz crucible, or alternativelythe resin tube is gradually raised in response to the progress of thefeeding of the polycrystalline silicon lumps, and the rosin tube iscompletely withdrawn from the quartz crucible at the end of feeding thepolycrystalline silicon lumps.

According to the fifth method, the bottom of the quartz crucible iscovered with pieces of polycrystalline silicon, grains ofpolycrystalline silicon, pure-water snow, or pure-water ice pieces, andthe inner sidewall of the quartz crucible is covered with a resin tube,then polycrystalline silicon lumps is fed into the quartz crucible. Theresin tube can be withdrawn from the quartz crucible at the end offeeding the polycrystalline silicon lumps. If the latter of the abovetwo methods is taken, since the resin tube is gradually raised inresponse to the progress of feeding the polycrystalline silicon lumps,the friction incurred between the resin tube and the polycrystallinesilicon lumps is very small. Furthermore the rosin tube can becompletely withdrawn from the quartz crucible at the and of feeding thepolycrystalline silicon lumps.

Furthermore, a process of feeding raw material into a quartz cruciblewithout using snow and ice as a shock-absorption material ischaracterized in that: before manufacturing silicon single crystal bythe CZ method, in the process of feeding polycrystalline silicon lumpsinto the quartz crucible, the bottom of the quartz crucible is tightlypacked with any one or a mixture of pieces of polycrystalline silicon orgrains of polycrystalline silicon; then the resin tube is graduallyraised in response to the progress of feeding the polycrystallinesilicon lumps, and the resin tube is completely withdrawn from thequartz crucible at the end of feeding the polycrystalline silicon lumps.

According to the above method, pieces of polycrystalline silicon orgrains of polycrystalline silicon protect the bottom of the quartzcrucible, and the resin tube protects the inner sidewall of the quartzcrucible. Therefore, like those employing snow/ice pieces as ashock-absorption material, the same effect can be obtained. In addition,treatments such an draining water and drying are not necessarysubsequent to the feeding of raw material.

In order to attain the above-mentioned object, the third apparatus forfeeding raw material into a quartz crucible according to the inventionis characterized in that: pure water is poured into a quartz crucible;piece-shaped icon, sherbet-shaped ices or their mixture made of purewater is fed into the quartz crucible; small piece-shapedpolycrystalline silicon, grain-shaped polycrystalline silicon or theirmixture is fed into the quartz crucible; lump polycrystalline silicon isloaded into the quartz crucible; and the quartz crucible andpolycrystalline silicon inside the quartz crucible are dried.

The polycrystalline silicon material can be rapidly fed into the quartzcrucible without the use of man-hand. Full pure water, piece-shaped orgrain-shaped polycrystalline silicon, piece-shaped ices floating on thepure water, etc. function as buffer materials of the lumppolycrystalline silicon. In addition to lump polycrystalline siliconfed, those buffer materials mentioned above are fed in the invention, soimpacts caused by the falling lump polycrystalline silicon can bealleviated, and damages to the quartz crucible can be prevented. Afterfeeding the raw material, the quartz crucible and polycrystallinesilicon inside the quartz crucible are dried.

The fourth apparatuses according to this invention are characterized inthat: a bucket for containing a quartz crucible is deeper than thequartz crucible; and means for moving the quartz crucible out of thebucket is provided.

The quartz crucible is contained in the bucket higher than the quartzcrucible. Then, the quartz crucible and bucket are filled with purewater and the horizon of the pure water is over the top of the quartzcrucible. That is, since pure water layer exits over the top of thequartz crucible, the buffer effect becomes larger especially insecond-half period of feeding lump polycrystalline silicon.

The fifth apparatus for feeding raw material into a quartz crucibleaccording to this invention is further characterized in that: a tube forsurrounding the inner sidewall of the quartz crucible is provided; andmeans for moving the tube upward and downward within a predeterminedrange is provided.

In the third apparatus for feeding raw material into a quartz crucible,the tube is used to moderate impacts against the inner sidewall of thequartz crucible when feeding the lump polycrystalline silicon. Since thetube is lowered and has completely covered the inner sidewall of thequartz crucible before feeding the lump polycrystalline silicon, thereare no damages on the sidewall of the quartz crucible.

Next, the fifth method for feeding raw material into a quartz crucibleaccording to the invention is characterized in that: before manufactureof single-crystal silicon, a quartz crucible is completely filled withpure water; and then lump polycrystalline silicon is fed into the purewater.

Since this method is the basin of the methods for feeding raw materialinto a quartz crucible of the invention, the pure water is used as abuffer material when feeding the lump polycrystalline silicon. Due tobuoyancy of the pure water causing the weight of the lumppolycrystalline silicon which is falling into the quartz crucible fullof the pure water to be reduced to about 60% of its original weight,impacts caused by the falling lump polycrystalline silicon can bemoderated, and therefore, damages to the quartz crucible can beprevented. Moreover, contamination substances stuck on the surfaces ofthe polycrystalline silicon can be removed by feeding thepolycrystalline silicon into the pure water.

Furthermore, the sixth method for feeding raw material into a quartzcrucible according to the invention is characterized in that: prior tomanufacture of single-crystal, a quartz crucible is inserted into abucket deeper than the quartz crucible; the quartz crucible and bucketare completely filled with pure water; and lump polycrystalline siliconis fed into the quartz crucible.

The quartz crucible is contained in the bucket higher than the quartzcrucible. Then, the quartz crucible and bucket are fully filled withpure water, and the horizontal level of the pure water is over the topof the quartz crucible. Under this condition, since the falling lumppolycrystalline silicon is applied with buoyancy in the last process offeeding raw material, impacts caused by the falling lump polycrystallinesilicon can be moderated.

The seventh method for feeding raw material into quartz crucibleaccording to the invention is further characterized in that: smallpiece-shaped or grain-shaped polycrystalline silicon or their mixturewith a predetermined thickness is disposed on the bottom of the quartzcrucible before feeding the lump polycrystalline silicon.

In the seventh method, since the bottom of the quartz crucible ispreviously covered by the small piece-shaped and/or grain-shapedpolycrystalline silicon, impacts of the falling lump polycrystallinesilicon directly to the bottom of the quartz crucible can be prevented.Therefore, the bottom of the quartz crucible can be efficientlyprotected.

The eighth method for feeding raw material into a quartz crucibleaccording to the invention is characterized in that: piece-shaped orsherbet-shaped icon or their mixture made of pure water is fed into thequartz crucible before loading the lump polycrystalline silicon.

The above-mentioned ices made of pure water, floating on the surface ofthe pure water, functions as the first buffer material. Moreover, in thelast process of feeding raw material, even though the final amount ofthe pure water in decreased, the floating ices can also functions as abuffer material.

The ninth method for feeding raw material into a quartz crucibleaccording to the invention is characterized in that: small piece-shapedor grain-shaped polycrystalline silicon or their mixture, andpiece-shaped or sherbet-shaped ices or their mixture made of pure waterare fed into the quartz crucible before feeding the lump polycrystallinesilicon.

Since the ninth method for feeding raw material into a quartz crucibleis combination of the third and fourth methods, the quartz crucible canbe well protected from damages from the beginning to the end of thefalling lump polycrystalline silicon.

the tenth method for feeding raw material into a quartz crucible ischaracterized in that, the inner sidewall of the quartz crucible iscovered with a tube which can freely move upward and downward beforefeeding the lump polycrystalline silicon; and the tube is separated withthe quartz crucible upon the and of feeding the lump polycrystallinesilicon, or the tube is raised corresponding to the process of feedingthe lump polycrystalline silicon and the tube is completely moved out ofthe quartz crucible upon ending the feeding of the lump polycrystallinesilicon.

In the tenth method, since the inner sidewall of the quartz crucible iswell protected by the tube during feeding raw material, the innersidewall cannot be harmed by impacts caused by the falling lumppolycrystalline silicon. Even though the tube is completely separatedwith the quartz crucible by the use of above-mentioned two methods afterthe feeding raw material is finished, since the tube is pulled up slowlyby the latter method corresponding to the process of feeding lumppolycrystalline silicon, frictions between the tube and lumppolycrystalline silicon are minimized, and therefore, impurities fallinginto the quartz crucible can be prevented.

According to theme methods, after feeding a predetermined amount ofpolycrystalline silicon into the quartz crucible, the polycrystallinesilicon and quartz crucible are dried.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading thesubsequent detailed description and examples with reference made to theaccompanying drawings, wherein:

FIG. 1 is a schematic illustration showing a method and an apparatus forfeeding raw material into a quartz crucible according to a firstembodiment;

FIG. 2 is a schematic illustration showing an apparatus for feeding rawmaterial into a quartz crucible according to a second embodiment;

FIG. 3 is a perspective view showing the structure of a resin tube;

FIG. 4 is a schematic illustration showing the structure of a draininghose according to a first embodiment;

FIG. 5 is a schematic illustration showing the structure of a draininghose according to a second embodiment;

FIG. 6 is a schematic illustration showing another method for feedingraw material into a quartz crucible according to the first embodiment;

FIG. 7 is a perspective view showing the structure of a ring shaped iceused in the method for feeding raw material into a quartz crucibleaccording to the second embodiment;

FIG. 8 is a schematic illustration showing the method for feeding rawmaterial into a quartz crucible according to the second embodiment;

FIG. 9 is a schematic illustration showing the method for feeding rawmaterial into a quartz crucible according to the third embodiment;

FIG. 10 is a schematic illustration showing another method for feedingraw material into a quartz crucible according to the third embodiment;

FIG. 11 is a schematic illustration showing the method for feeding rawmaterial into a quartz crucible according to the fourth embodiment;

FIG. 12 is a schematic illustration showing the method for feeding rawmaterial into a quartz crucible according to the fifth embodiment; and

FIG. 13 is a schematic view illustrating an apparatus for feeding rawmaterial according to the first embodiment of the invention;

FIG. 14 is a schematic view illustrating part of an apparatus forfeeding raw material according to second embodiment of the invention;

FIG. 15 is a schematic view illustrating an apparatus for feeding rawmaterial according to second embodiment of the invention;

FIG. 16 is a schematic view illustrating an apparatus for feeding rawmaterial according to sixth embodiment of the invention;

FIG. 17 is a perspective view illustrating a tube;

FIG. 18 is a schematic view illustrating an apparatus for feeding rawmaterial according to third embodiment of the invention;

FIG. 19 is a schematic view illustrating an apparatus for feeding rawmaterial according to fourth embodiment of the invention;

FIG. 20 is a schematic view illustrating an apparatus for feeding rawmaterial according to fifth embodiment of the invention; and

FIG. 21 is a schematic view illustrating an apparatus for feeding rawmaterial according to sixth embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following is a description of an embodiment of the method forfeeding raw material into a quartz crucible according to this invention,with references being made to the accompanying drawings. FIG. 1 is aschematic illustration showing a method and an apparatus for feeding rawmaterial into a quartz crucible according to a first embodiment. Asshown in FIG. 1, a quartz crucible 101 is steadily installed on asupport table 102, and a draining hose 103 having its end reaching thebottom of the quartz crucible 101 is extending along the inner wall ofthe quartz crucible 101. The quartz crucible 101, the draining hose 103,and a draining hose raising/lowering device (not shown) are capable ofbeing moved on a conveying device 104. Above the conveying device 104, acontainer 106 used for refrigerating ice baskets 105 formed by freezingpure-water or ring shaped ice (will be described hereinafter); acontainer 108 used for storing pieces of polycrystalline silicon, grainsof polycrystalline silicon, or their mixture (hereinafter referred aspiece/grain raw material 107); a container 110 used for storingpure-water snow, pure-water ice pieces, or their mixture (hereinafterreferred an snow/ice pieces 109); a container 112 used for storingpolycrystalline silicon lumps(hereinafter referred as lump material111); and a discharging hose 113 used for discharging heated pure waterare disposed on the conveying device 104 in such a manner that each iscapable of moving up and down without restraint. The above ice baskets105 are of a thickness of 2-3 cm and capable of being fixed within thequartz crucible 101. Although not shown in FIG. 1, the above ring shapedice is of a cylindrical shape and capable of being inserted into thequartz crucible 101. The ring shaped ice is capable of covering only theinner sidewall of the quartz crucible 101.

A plurality of turntables 114 are disposed on the conveying device 104,each is located below each of the container 109, the container 110, andthe container 112. The quartz crucible 101 conveyed and installed oneach turntable 114 can be rotated together with each correspondingturntable 114. Furthermore, the container 108, the container 110, andthe container 112 are capable of moving in the horizontal directionreciprocally within some extent and in synchronization with the rotatingmotion of each corresponding turntable 114 located therebelow.

A microwave oven 115 used for drying the quartz crucible 101 and the rawmaterial fed thereinto is disposed on the down-stream side of thedischarging home 113. The microwave oven 115 can accommodate and heatboth of the quartz crucible 101 and the support table 102. The microwaveoven 115 is provided with an air introducing port 115a for introducingflitted clean air and an air expelling port 115b for expellingwater-containing air. The conveying device 104 is passing by themicrowave oven 115 and extending to a preset location near asingle-crystal manufacturing device.

The conveying and the stopping of the quartz crucible 101; the raisingand the lowering of the container 106, the container 108, the container110, the container 112, the discharging hose 113, and the draining hose103; the reciprocal motions in the horizontal direction of the container108, the container 110, and the container 112; the beginning andstopping of the discharging of the content stored in each container; therotating and the stopping of each turntable 114; and the beginning andstopping of the operation of discharging water, draining water, and themicrowave oven 115 are respectively controlled basing on instructionsignals coming from a control device (not shown).

The above-described devices were listed on the purpose of satisfying allof the several methods described below. It should be noted that in somemethods for feeding raw material certain devices could be omitted.

FIG. 2 is a schematic illustration showing part of an apparatus forfeeding raw material into a quartz crucible according to the secondembodiment. FIG. 3 is a perspective view showing the structure of aresin tube used for covering the inner sidewall of a quartz crucible.Instead of the container 112 used for storing lump material 111 shown inFIG. 1, the apparatus for feeding raw material is provided with acontainer 121 and a resin tube 122 which is surrounding the container121 and capable of moving up and down without restraint. Same as thecontainer 112, the container 121 is capable of ascending, descending andmoving in the horizontal direction reciprocally. The resin tube 122 is acylinder capable of loosely covering the inner sidewall of the quartzcrucible when it descends, and is made of the same material as that ofthe bags packing the lump material 111. A slit 122a used for avoidinginterfering with the draining hose 103 shown in FIG. 1 is formed in theresin tube 122 which is affixed to two supporting rods 123. Furthermore,the resin tube 122 is capable of being rotated in synchronization withthe rotating motion of the quartz crucible. Other devices constructingthe apparatus for feeding raw material are the same to those shown inFIG. 1, and their description is thus omitted.

FIG. 4 is a schematic illustration showing the structure of a draininghose according to a first embodiment related to a draining hose. Thedraining hose is installed in the quartz crucible prior to feedingoperation and is used for draining the water left in the quartzcrucible. The water is melted from the snow and ice that is employed asshock-absorption material when lump material is loaded into the quartzcrucible. The hose 103 includes a resin hose body 103a, and apolycrystalline silicon pipe or a single-crystal silicon pipe 103b(hereinafter referred as silicon pipe) connected to the hose body 103aand is of a purity essentially the same as that of polycrystallinesilicon lumps. The silicon pipe 103b is somewhat longer than the depthof the quartz crucible 101. By employing the draining hose 103 havingthe above structure, only silicon pieces or silicon debris, which areproduced at the time of feeding lump material or produced by thescratching between the draining hose 103 and lump material duringwithdrawing the draining hose 103 from the quartz crucible 101, are leftwithin the quartz crucible 101. Therefore, destructive influence willnot brought on the lifting operation of single crystals. Furthermore,the silicon pipe 103b can also be left within the quartz crucible 101when the hose body 103a is withdrawn from the quartz crucible 101.

FIG. 5 is a schematic illustration showing the structure of a draininghose according to a second embodiment related to a draining hose. Asilicon pipe 103c covers a portion of the resin-made hose body 103a,which portion is inserting into the quartz crucible 101. The draininghose 103 shown in FIG. 5 has the same effect an that of the firstembodiment. At the beginning of withdrawing the draining hose 103, onlythe resin-made hose body 3a is withdrawn, then the silicon pipe 103c iswithdrawn. It is also advisable that the silicon pipe 103c is leftwithin the quartz crucible 101.

According to this invention, there are several methods for feeding rawmaterial into the quartz crucible. Their descriptions are set forthconsecutively. The method for feeding raw material into the quartzcrucible according to the first embodiment is that damping the shockimposing on the quartz crucible during feeding lump material byemploying pure-water snow/ice pieces. As shown in FIG. 1, the quartzcrucible 101 installed on the support table 102 is capable of beingconveyed between the container 106 and the container 108. Under thatsituation, the draining hose 103 is lowered and is disposed into thequartz crucible 101. The draining hose 103 is lowered until its one andreaches the bottom of the quartz crucible 101. Then, the quartz crucible101 is conveyed onto the turntable disposed under the container 110.Thereafter, the container 110 is lowered to a preset location so as tospray snow/ice pieces 109 from the container 110 onto the inner wall ofthe quartz crucible 101. Meanwhile, the quartz crucible 101 togetherwith the turntable is rotated, and the container 110 is driven to movein the horizontal direction reciprocally. Therefore, the inner wall ofthe quartz crucible 101 can be covered with a uniform-thick layer ofsnow/ice pieces 109. After the spray operation of snow/ice piece 109,the container 110 ascends to its original location.

Thereafter, the quartz crucible 101 is conveyed onto the turntable 114that is under the container 112, and the container 112 is lowered. Next,lump material is fed into the quartz crucible 101 through the container112. The shock during feeding lump material is damped by the snow/icepieces 109 sprayed onto the inner wall of the quartz crucible 101, andthe breakage of the quartz crucible 101 can be prevented. Furthermore,the quartz crucible 101 together with the turntable 114 is rotated, andthe container 112 is driven to move in the horizontal directionreciprocally. Therefore, lump material 111 can be uniformly fed into thequartz crucible 101, and lump material 111 can be tightly packed justlike hand operation.

During spraying snow/ice pieces 109 onto the inner wall of the quartzcrucible 101, snow/ice pieces 109 can be sprayed onto the inner sidewallfrom the lowermost location to uppermost location at one time.Alternatively, snow/ice pieces 109 is firstly sprayed from the lowermostlocation to a preset height, then repeats the same spray operation afterevery feeding of a preset amount of lump material.

After feeding a preset amount of lump material 111, the container 112ascends to its original location and the quartz crucible 101 is conveyedto a location below the discharging hose 113. At the location below thedischarging hose 113, pure water or heated pure water is discharged fromthe discharging hose 113 onto the lump material 111 so as to meltsnow/ice pieces 109. Thereafter, a draining pump (not shown) isactivated to drain out the water left in the quartz crucible 101 throughthe draining hose 103. Contamination substance stuck on lump material inthe processes of packing, transporting, or opening the packages will bewashed off by pure water that is drained out through the draining hose103. After draining the water, the draining hose 103 automatically goesup and leaves the quartz crucible 101.

After that, the support table 102 together with the quartz crucible 101fed with raw material is conveyed into the microwave oven 115 via theconveying device 104 and heated within a dust-removed air or nitrogenatmosphere. At that time, to prevent the occurrence of SiO₂ from lumpmaterial 111, heating temperature is controlled to avoid overheating.After removing water sticking on the quartz crucible 101 and lumpmaterial 111, the quartz crucible 101 is conveyed out of the microwaveoven 115 and transported to a preset location near the single-crystalmanufacturing device.

In the method for feeding raw material into a quartz crucible accordingto the first embodiment, it is also advisable that piece/grain rawmaterial can be tightly packed on the bottom of the quartz cruciblefirstly, then snow/ice pieces is sprayed thereover. Under thiscircumstance, in the device for feeding raw material into a quartzcrucible shown in FIG. 1, the quartz crucible 101 with the draining hose103 .installed thereon is conveyed under the container 108. At thattime, the container 108 is lowered to a preset extent and moves in thehorizontal direction reciprocally and the quartz crucible 101 togetherwith the turntable is rotated, meanwhile a preset amount of piece/grainraw material 107 is fed. Therefore, piece/grain raw material 107 couldbe tightly packed on the bottom of the quartz crucible 101 with anessentially even thickness. Next, the container 108 ascends to itsoriginal location, and the quartz crucible 101 is conveyed to a locationbelow the container 110, and snow/ice pieces 109 is sprayed over theabove piece/grain raw material 107 and the inner sidewall of the quartzcrucible 101. At that time, the quartz crucible 101 together with theturntable is also rotated, and the container 110 moves in the horizontaldirection reciprocally during its ascending or descending movements.Therefore, snow/ice pieces 109 could be tightly packed over thepiece/grain raw material 107 and the sidewall of the quartz crucible 101with an essentially even thickness. Then, an shown in FIG. 6, the quartzcrucible 101 is conveyed onto a turntable 114 that is disposed below thecontainer 112. Thereafter, lump material 111 is fed into the rotatingquartz crucible 101. In this embodiment, the protection on the bottom ofthe quartz crucible is extremely large. The treatment subsequent to thefeeding of raw material in the same as that described in the firstembodiment. The description is thus omitted.

The method for feeding raw material into a quartz crucible according tothe second embodiment is protecting the inner sidewall of the quartzcrucible by a ring shaped pure-water ice. In the device for feeding rawmaterial into a quartz crucible shown in FIG. 1, after installing thedraining home 103 on the quartz crucible 101, piece/grain raw material107 is tightly packed on the bottom of the quartz crucible 101. Then,pure-water snow/ice pieces 109 are sprayed over the above piece/grainraw material 107 discharged from the container 110. Thereafter, thequartz crucible 101 is conveyed to a location below the container 106,and a ring shaped ice 116 as shown in FIG. 7 is discharged from thedescended container 106. A slit 116a used for avoiding interfering withthe draining hose 103 is formed in the ring shaped ice 116. Afterinserting into the quartz crucible 101, the ring shaped ice 116 descendsalong the inner sidewall and covers the inner sidewall of the quartzcrucible 101 (see FIG. 9). Then, the quartz crucible 101 is conveyed toa location below the container 112, and lump material 111 stored in thecontainer 112 is fed into the quartz crucible 101. At that time, theinner sidewall of the quartz crucible 101 is protected from the impactof lump material 111 by the above ring shaped ice 116. Furthermore, itis also suitable that, before inserting the ring shaped ice 116, insteadof piece/grain raw material 107, snow/ice pieces 109 are directlysprayed onto the bottom of the quartz crucible. Furthermore, it is alsoacceptable to divide the ring shaped ice 116 into several sections alongits longitudinal axis and to insert the sections into the quartzcrucible in response to the amount of lump material fed. The treatmentsubsequent to the feeding of raw material is the same as that describedin the first embodiment, and the description is thus omitted.

In the method for feeding raw material into a quartz crucible accordingto the third embodiment, the quartz crucible 101 is conveyed to andstopped at a location below the container 106 shown in FIG. 1. Then, anice basket 105 descends from the container 106 and inserts into thequartz crucible 101. FIG. 9 is a schematic illustration showing themethod for feeding raw material into a quartz crucible according to thethird embodiment. As shown in FIG. 9, the draining hose 103 is loweredand installed after the ice basket 105 has been inserted. Then, thequartz crucible 101 is conveyed to a location below the container 112.At that time, the ice basket 105 has reached its melting temperature,and a layer of water is produced between the inner wall of the quartzcrucible 101 and the outer wall of the ice basket 105. Namely, the icebasket 105 is in a state of floating on the quartz crucible 101.

Under this circumstance, the container 112 is lowered to feed lumpmaterial 111 into the ice basket 105. At that time, the container 112moves in the horizontal direction reciprocally and the quartz crucible101 together with the turntable 114 is rotated. Therefore, the wholelump material 111 can be fed into the ice basket 105. After feeding lumpmaterial 111, pure water is discharged from the discharging hose 113onto lump material 111 to melt the ice basket 105. The subsequenttreatment is the same as that described in the first embodiment, and thedescription is omitted.

As shown in FIG. 10, in the method for feeding raw material into aquartz crucible according to the third embodiment, it is also advisableto tightly pack a preset amount of piece/grain raw material 107 storedin the container 108 firstly on the bottom of the ice basket 105 that isinserted into the quartz crucible 101 and floating thereon. Then, lumpmaterial 111 stored in the container 112 is fed after snow/ice pieces109 stored in the container 110 has been sprayed over the abovepiece/grain raw material 107. Alternatively, it is acceptable to spraysnow/ice pieces 109 firstly onto the inner surface of the tie basket 105inserted into the quartz crucible 101, then to feed lump material 111.The treatment subsequent to the feeding of raw material is the same anthat described in the first embodiment, and the description is thusomitted.

Furthermore, it is also satisfactory to reciprocally convey the quartzcrucible 101 between two locations respectively below the containers110, 112, and to alternatively feed snow/ice pieces 109 and lumpmaterial 111. This consecutive adding of shock-absorption materialduring the feeding of lump material 111 intensely impedes the impactincurred by dropping of lump material 111. Furthermore, it in alsosuitable to dispose the container 110 and the container 112 close toeach other. By this arrangement, subsequent to spraying snow/ice pieces109 onto the inner wall of the quartz crucible 101 with an eventhickness, snow/ice pieces 109 can be consecutively sprayed during thefeeding of the lump material 111.

The method for feeding raw material into a quartz crucible according tothe fourth embodiment is covering the inner sidewall of the quartzcrucible with a resin tube. In the device for feeding raw material intoa quartz crucible shown in FIG. 1, after installing the draining hose103 on the quartz crucible 108, the container 110 is lowered to spraypure-water snow/ice pieces 109 onto the bottom of the quartz crucible101. Alternatively, it is also satisfactory to lower the container 110to cover the bottom of the quartz crucible 101 with piece/grain rawmaterial 107, then spray pure-water snow/ice pieces 109 thereon.Thereafter, the quartz crucible 101 in conveyed to a location below thecontainer 121 shown in FIG. 2, and the resin tube 122 surrounding thecontainer 121 is lowered to insert into the quartz crucible 101 so as tocover the inner sidewall of the quartz crucible 101 (see FIG. 11). Atthat time, the draining home 103 installed on the quartz crucible 101 isin alignment with the alit 122a formed in the resin tube 122. Therefore)the resin tube 122 can be inserted into the quartz crucible 101 withoutinterfering with the draining hose 103.

Thereafter, the container 121 is lowered to a preset height to startfeeding lump material 111. Meanwhile, the container 121 is driven tomove in the horizontal direction reciprocally and the quartz crucible101 together with the turntable 114 is rotated. Therefore, lump material111 can be uniformly fed into the quartz crucible 101. Furthermore, theresin tube 122 is rotated in synchrony with the turntable 114; thereforeno friction is incurred between the resin tube 122 and the lump material111 fed into the quartz crucible 101. The bottom and the inner sidewallof the quartz crucible 101 are respectively covered by snow/ice pieces109 and the resin tube 122. Therefore, both are protected from theimpact induced by dropping of lump material 111, and they will not breakduring the feeding of lump material 111.

The resin tube 122 is gradually raised in response to the progress ofthe feeding of the lump material 111, and the resin tube 122 iscompletely withdrawn from the quartz crucible at the and of feeding thelump material 111. Then, the resin tube 122 ascends together with thecontainer 121 to its original height. The treatment subsequent to thefeeding of raw material is the same as that described in the firstembodiment, and the description is thus omitted.

In the above-described embodiments, lump material and piece/grain rawmaterial can be cleaned by pure water after feeding into the quartzcrucible. Therefore, it is possible to remove most of the contaminationbrought into in the processes of packing, transporting, opening thepackages, or even feeding lump material. Therefore, the problem incurredby unforeseen contamination that happened much more often than averagecan be solved. For example, the carbon content, the unforeseencontamination happened most often, can be substantially lowered to alevel of 0.6, and the metal content can also be lowered to a level of0.8.

The method for feeding raw material into a quartz crucible according tothe fifth embodiment is covering the quartz crucible with a resin tubeand piece/grain raw material without employing snow/ice pieces. Thefifth embodiment is an application of the fourth embodiment. Beforefeeding lump material 111, the container 108 is lowered (see FIG. 1) totightly pack piece/grain raw material 107 on the bottom of the quartzcrucible 101. Thereafter, the quartz crucible 101 is conveyed to alocation below the container 121 shown in FIG. 2, and the resin tube 122surrounding the container 121 is lowered to insert into the quartzcrucible 101 so as to cover the inner sidewall of the quartz crucible101 (see FIG. 12). Then, the container 121 is lowered to a presetfeeding height to start the feeding of lump material 111 just the sameas in the above fourth embodiment. Piece/grain raw material 107 and theresin tube 122 respectively cover the bottom and the inner sidewall ofthe quartz crucible 101. Therefore, both are protected from the impactinduced by dropping of lump material 111, and they will not break duringthe feeding of the lump material 111.

The resin tube 122 is gradually raised in response to the progress ofthe feeding of the lump material 111, and the resin tube 122 returns toits original height at the end of feeding the lump material 111.Meanwhile, the quartz crucible 101 fed with a preset amount of lumpmaterial 111 is conveyed to a preset location near the single-crystalmanufacturing device.

The method for feeding raw material into a quartz crucible according tothe fifth embodiment is using piece/grain raw material only as ashock-absorption material without employing resin tubes. At this time,to impede the shock imposing on the inner sidewall of the quartzcrucible during feeding lump material, the container 121 shown in FIG.12 is lowered to its lowermost location and is moved in the horizontaldirection reciprocally during the feeding operation. Thereafter, thecontainer 121 is gradually raised in response to the progress of thefeeding of the lump material. By this arrangement, lump material isplaced into the rotating quartz crucible without imposing any impact,and the breakage of the quartz crucible can thus be avoided.

Conventionally, the operation of feeding raw material into a quartzcrucible is performed by hand operation and is time-consuming. Accordingto this invention, it can be performed automatically by employingapparatuses with simple structures. Therefore, the operation of feedingraw material into a quartz crucible can be expedited and becomes laborsaving. Furthermore, in the process of feeding raw material, in additionto using pure-water snow and ice, heated pure water is poured to washoff contamination substance stuck on raw material. Therefore, thequality of silicon single crystals produced can be enhanced.Furthermore, in the process of feeding raw material into a quartzcrucible without using snow or ice, the structure of the apparatuses isvery simple and low cost. In light of the above, this invention is verycontributive to the enlargement of silicon single crystals produced bythe CZ method.

The embodiments of the present invention will be clearly described,accompanying with pertinent drawings. Referring to FIG. 13, a schematicview shows an apparatus for feeding raw material according to the sixthembodiment of the invention. A quartz crucible 201 is steadily disposedon a support table 202. The apparatus for feeding raw material comprisesmeans for raising/lowering a draining hose 203 with a length, one and ofwhich ia able to reach the bottom of the quartz crucible along innersidewall thereof, a water supply hose 204 for supplying pure water, acontainer 206 for storing small piece-shaped, grain-shapedpolycrystalline silicon or their mixture 205, a container 208 forstoring piece-shaped ices, sherbet-shaped ices or their mixture 207 madeof pure water, a container 210 for storing lump polycrystalline silicon209, a microwave oven 211 for containing and drying the quartz cruciblein which a predetermined amount of raw material is fed and a conveyer212 for carrying the quartz crucible. There are guide tubes 206a, 208a,210a at the bottoms of the containers 206, 208, 210, respectively.Moreover, the microwave oven 211 has an inlet 211a for guiding filteredpure air in and an outlet for discharging air containing moisture.

In order to drain the quartz crucible 201 to serve as an assistant meansfor rapidly drying raw material fed into the quartz crucible, thedraining hose 203 connected to a pump (not shown) is installed.Furthermore, the designed conveyer 212 is expected to stretch from thedownside of the water supply hose 204 to microwave oven 211, inparticular from microwave oven 211 to around an apparatus formanufacturing single-crystal (not shown). The container 206, 208, 210can be moved upward and downward. A freely rotatable turn table 213 isinstalled on the conveyer 212 under the containers. The quartz crucible201 can be rotated together with the support table 202 on the turn table213.

The conveying and stopping of the quartz crucible 201, the raising andlowering of the water supply hose and containers 206,208,210, thestarting and stopping of discharging the content stored in eachcontainer, starting and stopping of the turn table 213, the beginningand stopping of operations of supplying water, draining water and themicrowave oven 211 are respectively controlled by instruction signalscoming from a control device (not shown).

The above-described devices were listed on the purpose of satisfying allof the several methods described below. It should be noted that in somemethods for feeding raw material certain devices could be omitted.

FIG. 14 is a schematic view illustrating an apparatus for feeding rawmaterial according to the seventh embodiment of the invention. A bottomplate 214 is disposed on the topmost side of the conveyer 212. Acylinder 216 which can be moved upward and downward by the use of a rod215 over the bottom plate 214, surrounds the water supply hose 204 whichcan supply pure water. In addition, the cylinder 216 is much higher thanthe quartz crucible 201. A ring 217 is installed on the bottom ofcylinder 216. If the cylinder 216 is lowered to reach the cylinder 216then the cylinder 216 functions as a bucket containing the quartzcrucible 201 and support table 202 simultaneously. Furthermore, meansfor raising/lowering a draining hose, the same as that in the sixthembodiment, a container 206 for storing grain-shaped raw material 205, acontainer 208 for storing piece-shaped ices 207, a container 210 forstoring lump raw material 209 and microwave oven 211 are installed onthe downstream side of the bottom plate 214. However, it should not belimited that all of above-mentioned devices are necessary in certainmethods for feeding raw material.

FIG. 16 is a schematic view illustrating part of an apparatus forfeeding raw material according to the eighth embodiment of theinvention. This apparatus for feeding raw material comprise a container221 instead of the container 210 shown in FIG. 13 for storing lump rawmaterial and a tube 222 surrounding the container 221. The container 221can be raised/lowered, and moved back and fourth in horizontaldirection. The tube 222 is a cylinder which covers the inner sidewall ofthe quartz crucible when lowering the tube 222, is made of material thesame as that of bags used to pack the lump raw material 209, and isfixed on a rod 223 which can be freely raised and lowered. Referring toFIG. 17, in order to avoid obstacle caused by the draining hose 203shown in FIG. 13, there is a slit 222a designed on the side of the tube222. Furthermore, the tube 222 and turn table 213 (shown in FIG. 13) arecapable of being rotated in synchronization. Other devices constructingthe apparatus for feeding raw material are the same to those shown inFIG. 13, and their description is thus omitted.

Various methods for feeding raw material into a quartz crucibleaccording to the invention will be described hereinafter in order. Themethod for feeding raw material according to the sixth embodiment canmoderate impacts added to a quartz crucible, resulting from the fallinglump raw material, by use of pure water. In FIG. 13, the quartz crucible201 disposed on the support table 202 can be conveyed on the downside ofthe water supply hose 204. A draining hose 203 is lowered and disposedinside the quartz crucible 201. One end of the draining hose 203 islowered to reach the bottom of the quartz crucible 201. After that, thequartz crucible 201 is conveyed just under the water supply hose 204,and pure water is supplied to the quartz crucible 201 from the watersupply hose 204. The quartz crucible 201 full of pure water is conveyedonto a turn table 213 installed under a container 210. Then, lump rawmaterial 209 is fed into the quartz crucible 201 from the container 210which is lowered to a predetermined position. Due to buoyancy of thepure water, the weight of the dropping lump raw material 209 is reducedto about 60% of its original weight. Therefore, impacts applied to thequartz crucible 201 can be obviously moderated, and damages to thequartz can be prevented. In addition, since the quartz crucible 201 isrotated together with the turn table 213, the lump raw material 209 canbe equally fed into the quartz crucible 201 with a density the same asthat in the man-hand operation.

As a predetermined mount of the lump raw material 209 has been fed, thecontainer 210 is raised to the original position. A draining pump (notshown) connected to the draining hose 203 is driven to drain the purewater out of the quartz crucible 201.

Contamination substances created by processes of packing, conveying,opening, etc. for the lump polycrystalline silicon 209 are washed out byuse of the pure water, and then discharged out through the draining hose203. After draining, the draining hose 203 is automatically pulled upand retracted from the quartz crucible 201.

Thereafter, the quartz crucible 201 fed with raw material is conveyedinto the microwave oven 211 together with the support tale 202, and thenheated at an environment full of dust-removed air or nitrogen. At thistime, in order to prevent SiO₂ from being created on the lump rawmaterial 209, the heating temperature should be wall controlled to avoidoverheat. After moisture adhesive on the quartz crucible 201 has beenremoved, the quartz crucible 201 is moved out of the microwave oven 211,and conveyed to a predetermined position near to an apparatus formanufacturing single-crystal by CZ method.

FIG. 14 is a schematic view showing an apparatus for feeding rawmaterial according to the seventh embodiment of the invention. A quartzcrucible 201 is conveyed together with a support table 202 onto a bottomplate 214. A cylinder 216 installed on a rode 215 is lowered to pressagainst the bottom plate 214. Therefore, the quartz crucible 201 andsupport table 202 is contained in a bucket constructed by the cylinder216 and bottom plate 214. At this point, a draining hose 203 is loweredand disposed in the quartz crucible 201, as shown in FIG. 15. One and ofthe draining hose 203 is lowered to reach the bottom of the quartzcrucible 201; the other and of the draining hose 203 passes over the topof the bucket 218 to connect to a draining pump (not shown). Next, purewater is supplied from the water supply hose 204. The bucket 218 iscompleted filled with pure water following that the quartz crucible 201has been full of pure water.

The bucket 218 and quartz crucible 201 full of pure water are conveyedonto the turn table 213 disposed under the container 210 an shown inFIG. 15. The lump raw material 209 is fed into the quartz crucible 201which is rotated together with the bucket 218, from the container 210.Since buoyancy caused by the pure water is applied on the lump rawmaterial 209, impacts added to the quartz crucible 201 are obviouslymoderated. Moreover, since a layer of pure water exists between the topsof the quartz crucible 201 and bucket 218, buoyancy is applied to thefalling lump raw material 209, and therefore impacts added to the quartzcrucible 201, resulting from the falling raw material, can beeliminated.

If a predetermined amount of lump raw material 209 is fed into thequartz crucible 201, the bucket 218 is conveyed on the downstream sideof the container 210, and only the cylinder 216 is raised. Therefore,the pure water inside the bucket 218 in discharged through a gap betweenthe cylinder 216 and bottom plate 214. After that, a draining pump (notshown) connected to the draining home 203 is driven to discharge thepure water out of the quartz crucible 201 with the draining hose 203therein. Contamination substances created by processes of packing,conveying, opening, etc. for the lump polycrystalline silicon 209 arewashed out by use of the pure water, and discharged out through thedraining hose 203. After draining, the draining hose 203 isautomatically pulled up and retracted from the quartz crucible 201. Inaddition, the cylinder 216 is raised to the original height. Thedescription for a subsequent drying process which is the same as thatstated in the sixth embodiment of the invention is omitted.

In the eighth embodiment of the invention, pure water and smallpiece-shaped or grain-shaped raw material are used as buffer materialsfor the falling raw material which will be fed into a quartz crucible.In the apparatus for feeding raw material as shown in FIG. 13, the drainhose 203 is disposed, and the quartz crucible 201 full of pure water isconveyed onto the turn table installed under the container 206. At thistime, The quartz crucible 201 is rotated together with the support table202, and small piece-shaped or grain-shaped material 205 is fed into thequartz crucible 201 from the container 206. After the bottom of thequartz crucible 201 has been covered with small piece-shaped orgrain-shaped material with a thickness of above 3 cm, the quartzcrucible 201 is conveyed onto the turn table 213 installed under thecontainer 210 as shown in FIG. 18, and then lump raw material 209 is fedinto the quartz crucible 201 from the container 210. If a predeterminedamount of raw material is fed into the quartz crucible 201, a drainingpump (not shown) connected to a draining hose 203 is driven to dischargethe pure water inside the quartz crucible 201, and then the draininghose 203 is retracted from the quartz crucible 201. The description fora subsequent drying process which is the same as that stated in thesixth embodiment of the invention will be omitted here. Theabove-mentioned method for feeding raw material is also suitable to theseventh embodiment shown in FIG. 14.

In the ninth embodiment of the invention, pure water and piece-shapedices are used as buffer materials for the falling lump raw materialwhich will be fed into a quartz crucible. In an apparatus for feedingraw material as shown in FIG. 13, a draining hose 203 is installed, anda quartz crucible 201 completely filled with pure water is conveyed ontoa turn table disposed under a container 208. At this point, the quartzcrucible 201 is rotated together with a support table 202, andpiece-shaped ices 201 are fed into the quartz crucible 201 from thecontainer 208. The piece-shaped ices float on the surface of the purewater fully inside the quartz crucible 201 without gaps. If apredetermined amount of piece-shaped ices 207 are fed into the quartzcrucible 201, the quartz crucible 201 is conveyed onto a turn table 213installed under a container 210 as shown in FIG. 19, and then lumpmaterial 209 is fed into the quartz crucible 201 from the container 210.The falling speed of the lump raw material 209 is decreased by thefloating ices 207. In addition, the lump raw material 209 is appliedwith buoyancy of the pure water. Since the process after feeding apredetermined amount of raw material into the quartz crucible 201 is thesame as that in the eighth embodiment, their description is omittedhere. Meanwhile, the method for feeding raw material according to theninth embodiment is suitable to the seventh embodiment shown in FIG. 14,and the piece-shaped of ices may float inside the bucket.

A method for feeding raw material according the tenth embodiment iscombination of those of the eighth embodiment and the ninth embodiment.In an apparatus for feeding raw material as shown in FIG. 13,piece-shaped or grain-shaped of raw material is first fed into a quartzcrucible 201 full of pure water, from a container 206. Therefore, thebottom of the quartz crucible 201 is covered with the small piece-shapedor grain-shaped of raw material. Next, piece-shaped ices are fed from acontainer 208, and float on the surface of the pure water fully insidethe quartz crucible 201 without any gaps. Thereafter, the quartzcrucible 201 is conveyed onto a turn table 213 installed under acontainer 210 an shown in FIG. 20. Then, lump raw material 209 is fedinto the quartz crucible 201 from the container 210. Therefore, thefalling speed of the lump raw material 209 is reduced by thepiece-shaped ices 207. Moreover, the lump raw material 209 is appliedwith buoyancy of the pure water, and accumulate on the smallpiece-shaped or grain-shaped raw material 205. Since the process afterfeeding a predetermined amount of raw material into the quartz crucibleis the same to that in the eighth embodiment, their description isomitted here.

The method for feeding raw material according to the tenth embodiment issuitable to the seventh embodiment shown in FIG. 14.

In a method for feeding raw material according to the eleventhembodiment, the inner sidewall of a quartz crucible is covered with atube. A draining hose 203 is disposed in a quartz crucible 201 as shownin FIG. 21. After the quartz crucible 201 is completely filled with purewater which is supplied through a water supply hose, the quartz crucible201 is conveyed onto a turn table 213 installed under a container 221.At this time, a tube 222 (shown in FIGS. 16 and 17) surrounding thecontainer 221 is lowered to insert into the quartz crucible 201, so thatthe inner sidewall of the quartz crucible 201 in totally cover by thetube 222. At this moment, since the position of the draining hose 203disposed into the quartz crucible 201 is consistent with that of a slit222a on the side of the tube 2122, the draining hose 203 is not able tointerfere with inserting the tube 222 into the quartz crucible 201.

After that, the container 221 is lowered to a predetermined feedingposition, and then lump raw material 209 in fed from the container 221.At this time, since the quartz crucible 201 is rotated together with aturn table 213, and the container 221 is moved back and forth inhorizontal direction with a predetermined stroke, the lump raw material209 can be evenly fed into the quartz crucible 201. Furthermore, sincethe tube 222 is rotated in synchronization with the turn table 213,frictions between the lump raw material 209 fed into the quartz crucible201 and the tube 222 is eliminated. The inner sidewall of the quartzcrucible is completely covered by the tube 222, so impacts caused by thefalling lump raw material 209 can be prevented, and therefore, there areno damages added to the quartz crucible 201.

The tube 222 is slowly raised in line with the process of feeding thelump raw material 209, and then entirely separated with the quartzcrucible 201 after feeding lump raw material 209 is end. In addition,the tube 222 is raised to the original position together with thecontainer 221. Since the process after feeding a predetermined amount ofraw material into the quartz crucible 201 is the same as that in theeighth embodiment, their description is omitted. The method for feedingraw material according to the eleventh embodiment is suitable to theseventh embodiment shown in FIG. 14.

In the method for feeding raw material according to the eleventhembodiment, before feeding the lump raw material 209 into the quartzcrucible 201, the piece-shaped or grain-shaped raw material 205 may befed from the container 206 to cover the bottom of the quartz crucible201, and piece-shaped ices 207 may be fed from the container 208 asshown in FIG. 13. According to this method, the inner sidewall of thequartz crucible 201 can be wall protected by the tube 222, and thebottom side of the quartz crucible 201 can be efficiently protected bythe small piece-shaped or grain-shaped raw material or the smallpiece-shaped or grain-shaped raw material and ices. Therefore, impactscaused by the falling lump raw material 209 can be markedly alleviated.

In the all embodiments described above, since the lump raw material andsmall piece-shaped or grain-shaped raw material are washed out bydisposing them into the pure water, most of contamination substancescreated during processes of packing, conveying, opening, etc. for thelump polycrystalline silicon 209 are removed, and contamination causedby man-hand in the past never occurs. Therefore, the problem ofcreated-suddenly contamination higher than the average contaminationstandard can be resolved. For example, in the created-suddenlycontamination, the level of the most high-frequently created containedcarbon is lower than about 0.8, and the level of contained metal is alsolower than about 0.8.

According to the invention described above, since feeding raw materialinto a quartz crucible in performed by using combination of apparatuseswith simple structures instead of man-hand operation of the prior art inwhich longer operation time in needed, labor-saving function and rapidoperation can be achieved. Furthermore, since pure water is used as abuffer material during feeding raw material, contamination substancesadhesive to the raw material are cleaned out, and therefore, the qualityof grown single-crystal silicon is better than that in prior art. Basedon those advantages of the invention, maximization in diameter andweight for manufacturing single-crystal silicon by CZ method can beefficiently attained.

What is claimed is:
 1. An apparatus for feeding raw material into acrucible, which is used for feeding polycrystalline silicon as rawmaterial into a crucible before manufacturing silicon single crystal bythe CZ method, which comprises:means for feeding polycrystalline siliconlumps into the crucible; means for covering an inner wall of thecrucible with a buffer of any one or a mixture selected from a group ofpieces of polycrystalline silicon, grains of polycrystalline silicon,pure-water snow, sherbet-shaped pure-water ice, pure-water ice pieces,and pure-water ice; means for draining a liquid melted from the bufferfrom the crucible; and means for drying the crucible and thepolycrystalline silicon fed into the crucible.
 2. The apparatus forfeeding raw material into a crucible as claimed in claim 1, furthercomprising means for rotating and transporting the crucible.
 3. Theapparatus for feeding raw material into a crucible as claimed in claim1, further comprising:a resin tube capable of covering the inner wall ofthe crucible; means for moving up and down the resin tube; and means forrotating the resin tube at a speed equivalent to that of the crucible.4. The apparatus for feeding raw material into a crucible as claimed inclaim 1, further comprising:means for moving said feeding means and saidcovering means up and down and reciprocally in a horizontal directionrelative to the crucible.
 5. The apparatus for feeding raw material intoa quartz crucible as claimed in claim 1, further comprising:means forautomatically controlling at least one of said means for feedingpolycrystalline silicon lumps; means for covering; means for draining;and means for drying.
 6. The apparatus for feeding raw material into acrucible as claimed in claim 1, whereinthe draining means comprises adraining hose having an insert part which is inserted into the crucibleso as to drain the liquid melted from the buffer, the insert part ismade of one of: one of a polycrystalline silicon pipe and asingle-crystal silicon pipe and one of a pipe coated by apolycrystalline silicon pipe or a single-crystal silicon pipe.
 7. Theapparatus for feeding raw material into a crucible as claimed in claim1, further comprising:means for supplying pure water into the crucible.8. The apparatus for feeding raw material into a crucible as claimed inclaim 7, further comprising:a bucket for containing said crucible, saidbucket having a depth which is greater than a depth of said crucible;and means for moving said crucible out of said bucket.
 9. The apparatusfor feeding raw material into a crucible as claimed in claim 7, furthercomprising:a tube for covering the inner wall of said crucible; andmeans for moving said tube upward and downward.
 10. An apparatus forfeeding raw material into a crucible, which is used for feeding siliconas raw material into a crucible before manufacturing silicon singlecrystal by the CZ method, comprising:means for feeding silicon lumpsinto the crucible; means for supplying water into the crucible toprovide buoyancy against the silicon lumps fed into the crucible; meansfor draining the water from the crucible; and means for drying thecrucible and the silicon fed into the crucible.
 11. An apparatus forfeeding raw material into a crucible, which is used for feeding siliconas raw material into a crucible before manufacturing silicon singlecrystal by the CZ method, comprising:a container for feeding siliconlumps into the crucible; a container for dispensing a buffer within thecrucible, the buffer comprised of at least one of: pieces of silicon,grains of silicon, water snow, sherbet-shaped water ice, water icepieces, and water ice for covering an inner wall of the crucible withthe buffer; a drain pipe for draining from the crucible a liquid meltedfrom the buffer; and a dryer for drying the crucible and the silicon fedinto the crucible.
 12. An apparatus for feeding raw material into acrucible, which is used for feeding silicon as raw material into acrucible before manufacturing silicon single crystal by the CZ method,comprising:a container for feeding silicon lumps into the crucible; apipe and water supply for supplying water into the crucible to providebuoyancy against the silicon lumps fed into the crucible; a pipe fordraining the water from the crucible; and a dryer for drying thecrucible and the silicon fed into the crucible.